Wi-Fi connected but does not downloadSupport

My phone (Cricket Huawei Ascend Android 2.1) will connect to the Wi-Fi network but when I open an app like YouTube I receive the error "There is no network connection right now." If I try downloading an app from the market the download will start but then it pauses itself and wont ever finish downloading, not even one percent of it. But when I connect to my brother's Wi-Fi in his home it works just fine. Even weirder is that it used to work months ago and now all of a sudden it doesn't

My phone (Cricket Huawei Ascend Android 2.1) will connect to the Wi-Fi network but when I open an app like YouTube I receive the error "There is no network connection right now." If I try downloading an app from the market the download will start but then it pauses itself and wont ever finish downloading, not even one percent of it. But when I connect to my brother's Wi-Fi in his home it works just fine. Even weirder is that it used to work months ago and now all of a sudden it doesn't

Sorry awgz17 I should have been clearer-if possible totally reset the router.
Most have a reset button in the back of the router(very small-usually need a paperclip end to fit in there to reset it).
If that doesn't fix the problem reset the router using the setup disk it came with(like the day it was first setup).
If the above is an option for you(your router).